Reports of cryptic species causing aspergillosis in humans are increasing in the literature. Cryptic species are defined as those which are morphologically indistinguishable, although their identifications can be confirmed using molecular or other techniques which continue to become more widely available in the clinical setting. Antifungal resistance has often been noted in these cases, and indeed there does appear to be a higher prevalence of reduced susceptibility in cryptic species. Many of these observations are published as individual case reports or as a small component of larger data sets, making it challenging to review and compare the data fully. This review article seeks to describe the susceptibility trends and key learning outcomes of specific cases of infections caused by cryptic species, including Aspergillus alliaceus, Aspergillus calidoustus, Aspergillus felis, Aspergillus lentulus, Aspergillus tubingensis, Aspergillus viridinutans and Neosartorya pseudofischeri. These reports highlight the clinical need for full accurate identification and susceptibility testing to guide patient care.